/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License.  You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package org.apache.flink.api.java.typeutils;

import org.apache.flink.annotation.Public;
import org.apache.flink.annotation.PublicEvolving;
import org.apache.flink.api.common.ExecutionConfig;
import org.apache.flink.api.common.serialization.SerializerConfig;
import org.apache.flink.api.common.typeinfo.AtomicType;
import org.apache.flink.api.common.typeinfo.TypeInformation;
import org.apache.flink.api.common.typeutils.TypeComparator;
import org.apache.flink.api.common.typeutils.TypeSerializer;
import org.apache.flink.api.common.typeutils.base.EnumComparator;
import org.apache.flink.api.common.typeutils.base.EnumSerializer;

import static org.apache.flink.util.Preconditions.checkNotNull;

/**
 * A {@link TypeInformation} for java enumeration types.
 *
 * @param <T> The type represented by this type information.
 */
@Public
public class EnumTypeInfo<T extends Enum<T>> extends TypeInformation<T> implements AtomicType<T> {

    private static final long serialVersionUID = 8936740290137178660L;

    private final Class<T> typeClass;

    @PublicEvolving
    public EnumTypeInfo(Class<T> typeClass) {
        checkNotNull(typeClass, "Enum type class must not be null.");

        if (!Enum.class.isAssignableFrom(typeClass)) {
            throw new IllegalArgumentException(
                    "EnumTypeInfo can only be used for subclasses of " + Enum.class.getName());
        }

        this.typeClass = typeClass;
    }

    @Override
    @PublicEvolving
    public TypeComparator<T> createComparator(
            boolean sortOrderAscending, ExecutionConfig executionConfig) {
        return new EnumComparator<T>(sortOrderAscending);
    }

    @Override
    @PublicEvolving
    public boolean isBasicType() {
        return false;
    }

    @Override
    @PublicEvolving
    public boolean isTupleType() {
        return false;
    }

    @Override
    @PublicEvolving
    public int getArity() {
        return 1;
    }

    @Override
    @PublicEvolving
    public int getTotalFields() {
        return 1;
    }

    @Override
    @PublicEvolving
    public Class<T> getTypeClass() {
        return this.typeClass;
    }

    @Override
    @PublicEvolving
    public boolean isKeyType() {
        return true;
    }

    @Override
    @PublicEvolving
    public TypeSerializer<T> createSerializer(SerializerConfig serializerConfig) {
        return new EnumSerializer<T>(typeClass);
    }

    // ------------------------------------------------------------------------
    //  Standard utils
    // ------------------------------------------------------------------------

    @Override
    public String toString() {
        return "EnumTypeInfo<" + typeClass.getName() + ">";
    }

    @Override
    public int hashCode() {
        return typeClass.hashCode();
    }

    @Override
    public boolean canEqual(Object obj) {
        return obj instanceof EnumTypeInfo;
    }

    @Override
    public boolean equals(Object obj) {
        if (obj instanceof EnumTypeInfo) {
            @SuppressWarnings("unchecked")
            EnumTypeInfo<T> enumTypeInfo = (EnumTypeInfo<T>) obj;

            return enumTypeInfo.canEqual(this) && typeClass == enumTypeInfo.typeClass;
        } else {
            return false;
        }
    }
}
